Range hoods, exhaust fans, or other air handling apparatus have long been used in home, commercial, and industrial environments to assist in treating (e.g., filtering) or removing pollutants or other emissions. Various attempts have been made to compare the relative effectiveness of one air handling system to another, particularly in relation to air handling apparatus for use in exhausting or filtering cooking emissions. In one approach, an amount of emissions captured by a range hood can be assessed indirectly. For example, this can be accomplished by mechanically measuring an exhaust flow rate through an aperture such as an exhaust duct. However, while such an approach can provide a numerical result (e.g., cubic feet per minute (CFM)) such indirect assessment has drawbacks because it only considers one aspect of range hood efficiency and may deliver biased results. For example, such an approach does not provide information as to the spatial coverage or “reach” of the air handling apparatus being evaluated.
In another approach, ASTM standard F1704-05, “Standard Test Method For Capture and Containment Performance of Commercial Kitchen Exhaust Ventilation Systems” provides a method of measuring an exhaust flow rate through an air system using flow visualization to determine the threshold of capture and containment (C&C) of a hood/appliance combination under cooking and idle conditions.